I just bought a Tripp-Lite Isobar4Ultra. My Protection Present light is on but dim. My Fault light is on as is the Line OK line. The last 2 tell me the outlet is ok (Line OK) but the outlet probably isn't grounded (Fault light). My house was built in 1930 and the outlets aren't grounded. Supposedly the entire house is grounded, not the individual circuits. That said, does this mean the suppressor won't protect my stove, or will it still function the way it should??